Add support for maxNoOfLabels in label tool

- Add support for maxNoOfLabels in label tool.

- Close edit mode of label on datapoint click.
Fix shift of label when a label is in edit mode

- Shift label on datapoint click when a label is in edit mode in
  LABEL_ONE state.
Initial commit for text wrap within label

- Initial commit for text wrap within label.
Fix text cut-off bug

- Fix text cut-off bug on wrap of text in the label.
Stop update of text on drag when in edit mode

- Stop update of text on drag when in edit mode.
Avoid scrollbar within the text-area

- Avoid scrollbar within the text-area when more then three lines are
  present.
Avoid call to 'beginEditing' when in edit mode

- Avoid 'beginEditing' call from 'doubleClick' when label is already in
  edit mode.
Fix some label render issues on IE8

- Fix some label render issues on IE8 when label is under drag and in
  edit mode.
Block edit mode of label on exitState

- Block edit mode of label on exitState of 'MANY_LABEL' state.
Tweaks for IE8

- Give a space instead of blank text for IE8.

- Avoid creation of new label when mouse down on graph area for IE8.
Maintain proper z-order between label and legend

- Maintain proper z-order between label and legend.
Update integration and unit test

- Update integration and unit test for label_tool.
Fix 'connectingLine' behaviour of label

- Fix 'connectingLine' behaviour of label when label is too close to
  datapoint.
Merge branch 'zeus_rebase_02_28_13_a'
Lint fixes (trailing whitespace, extraneous comma)